In general, a personal computer, portable communication equipment, and other personal information processing devices construct an interface with a user through various input devices such as a keyboard, a mouse, and a digitizer.
Meanwhile, as the usage of the personal computer is expanded, the degree of the finishing of the product may not be enhanced only by using the keyboard and the mouse. Accordingly, the demand for a portable input device having a simpler structure while reducing an erroneous operation is gradually increased as time elapses.
In order to meet the demand, there is suggested a touch panel in which a user directly touches a screen by using the hand of the user or a pen to input information. The touch panel has a simple structure, represents less erroneous operations, and can be easily carried. In addition, the touch panel enables a user to input characters without other input devices and to easily learn how to use the touch panel. Recently, due to the advantages, the touch panel has been applied to various information processing devices.
In order to detect the coordinates of a touched position, such touch panels are classified into a resistive-type touch panel to determine the touched position based on voltage gradient varied according to resistances in the state that metallic electrodes are provided on top and bottom plates and DC voltage is applied to the metallic electrodes, a capacitive-type touch panel to detect a position having voltage variation between the top and bottom plates according to the touch by forming equipotential in a conductive film, or an electro-magnetic-type touch panel to detect the touched position by reading an LC value induced as an electronic pen touches a conductive film